Peter Thiel

Early Facebook investor Peter Thiel has another huge winner with big-data consultancy Palantir Technologies, which he also cofounded. Palantir raised money in December at a $9 billion valuation, making Thiel's estimated 12% stake (the largest) worth more than $1 billion. Thiel, a cofounder of PayPal, still sits on Facebook's board but sold most of his 10% stake in the social networking company following its May 2012 IPO. His various venture firms include Founders Fund, whose stated goal is to invest in companies that it says can affect dramatic technological change. Notable investments include Airbnb, Practice Fusion and payments company Stripe. Ideological to the point of eccentricity, Thiel believes technology rarely repeats itself: "There's a sense in which technology is, by definition, non-repetitive. And every moment in technological history only happens once." As Palantir's chairman, Thiel has personally invested $40 million in the Palo Alto, Calif. firm. He firmly believes the company could be just as valuable as Facebook.